Upgraded flight management system and method of providing the same

ABSTRACT

A preexisting FMS system may be upgraded to increase its functionality while still taking advantage of certain components of the legacy system previously provided on the aircraft and replacing other preexisting components with different components for enhancing the functionality of the FMS system. The preexisting IRU, CADC, DME receiver and DFGC in the upgraded FMS system are in communication with the legacy AFMC but, instead of employing the legacy EFIS which existed in the preexisting FMS system, the EFIS is replaced by a data concentrator unit as well as the display control panel and integrated flat panel display, and a GPS receiver. The upgraded FMS system is capable of such increased functionality as increased navigation database storage capacity, RNP, VNAV and RNAV capability utilizing a GPS based navigation solution, and RTA capability, while still enabling the legacy AFMC to exploit its aircraft performance capabilities throughout the flight.

FIELD OF THE INVENTION

The present invention relates generally to flight management systems(“FMS”) for use on board an aircraft, such as for interfacing with theflight crew and assisting in the control of an aircraft throughoutflight, and more particularly relates to the upgrading of preexistingflight management systems previously provided on the aircraft in orderto update the preexisting FMS to provide increased functionality whileattempting to cannibalize and optimize the utilization of various costlycomponents of the preexisting on board flight management system.

BACKGROUND OF THE INVENTION

The longevity of aircraft, particularly aircraft used in commercialaviation, usually far exceeds changes in the level and capabilities ofon board equipment used to assist the flight crew in controlling theaircraft. Thus, the aircraft manufacturer, or the customer, such as acommercial airline, in their desire to upgrade their equipment with thelatest technology, such as regarding on board flight management systems(“FMS”) is faced with considerable expense, and downtime, in attemptingto upgrade the existing aircraft with the latest technology. In manyinstances, particularly regarding commercial aviation, this may not be amere matter of competitive choice but may be mandated by a regulatoryagency, such as the Federal Aviation Administration. In the case ofcommercial fleets involving substantial numbers of aircraft this can bequite costly and time consuming, but necessary as the cost of theaircraft involved, and the time to construct them, leaves very littlechoice but to retrofit the existing fleet.

One such area where there have been considerable changes which improvethe capability and efficiency of the aircraft is in the area of flightmanagement systems which have now needed to be updated to keep up notonly with competitive pressures, but with the latest capabilities andfunctionality desired by the FAA as well. A typical example of this iswith respect to the preexisting flight management system on board atypical conventional MD-80/90 aircraft which is a work horse of manyairline fleets and has been utilized by the airlines for many years.Such aircraft, despite their long use, still have many flying hours leftbut need the preexisting on board flight management system to bereplaced or upgraded to keep up with modern needs and requirements.These preexisting systems, such as the preexisting flight managementsystem on board a typical MD-80/90 aircraft, which were satisfactorywhen they were originally installed on board the aircraft, and havepreviously been for several years thereafter, generally have a legacyEFIS system which, in today's environment, results in various existingsystem shortcomings, such as providing limited FMS Navigation databasestorage capacity, lacking a desired required time of arrival or RTAcapability, and lacking the ability to provide RNP VNAV and RNAVcapability utilizing a GPS or global positioning system based navigationsolution.

Prior art efforts in this area, in order to meet these and other currentneeds in preexisting aircraft still having considerable life, haveinvolved the often costly and inefficient complete replacement of thepreexisting flight management system with an entirely new system. Thiswas the typical approach previously utilized rather than attempting totake advantage of various key legacy components in a retrofitted system,such as by overcoming these preexisting system shortcomings by replacingthe legacy EFIS system with other components while optimizing the usageof preexisting legacy components from the prior on board flightmanagement system, such as the legacy advance flight management computeror AFMC which in the navigation solution utilized on preexistingaircraft, such as the MD-80/90, relies on a single AFMC to calculatesuch parameters as lateral guidance, vertical guidance, and performancecalculations. Thus, it would be desirable in any navigation upgradesolution for preexisting aircraft to be able to retain the legacy AFMCin any upgraded navigation solution for that aircraft, rather thanreplace the preexisting FMS system completely so as to be able, interalfa, to exploit the previously proven performance capabilities of theon board AFMC. In addition, because these preexisting flight managementsystems were not originally intended to utilize the type of GPS basednavigation solutions preferred today, they did not have the capabilityof utilizing a GPS based navigation solution, such as to provide RNPVNAV and RNAV capability.

Accordingly, a need or potential for benefit exists for viable upgradedflight management systems that can take advantage of and retrofit orcannibalize preexisting on board FMS system components, including the onboard AFMC, in order to efficiently and cost effectively upgrade thecapabilities of the preexisting FMS system without having to completelyreplace it.

SUMMARY OF THE INVENTION

In accordance with the present invention, a preexisting flightmanagement system or FMS, such as a legacy MD-80/90 FMS system, isupgraded to increase its functionality while still employing certainpreexisting components of the legacy system, such as the advanced flightmanagement computer or AFMC, the inertial reference unit or IRU, thecentral air data computer or CADC, the DME receiver, and the digitalflight guidance computer or DFGC, while replacing other preexistingcomponents, such as the legacy EFIS system, with different componentsproviding enhanced functionality for the FMS system. In thereconstituted or upgraded flight management system of the presentinvention, the preexisting IRU, CADC, DME receiver and DFGC remain incommunication with the legacy AFMC but, instead of utilizing the legacyelectrical flight information system or EFIS system from the preexistingFMS system, the EFIS system is replaced by a data concentrator unit aswell as a display control panel and an integrated flat panel display,and a global positioning system or GPS receiver is added to the systemto enable a GPS based navigation solution to be provided. The dataconcentrator unit and the legacy AFMC are operatively connected to eachother for exchanging information therebetween, with the DFGC beingconnected to the data concentrator unit output. The GPS or globalpositioning system receiver is operatively connected to the dataconcentrator for providing input information thereto. The upgraded FMSsystem of the present invention is capable of at least increasednavigation database storage capacity and/or RNP, VNAV and RNAVcapability utilizing a GPS based navigation solution and may haverequired time of arrival or RTA capability as well, while still enablingthe legacy AFMC to exploit its aircraft performance capabilitiesthroughout the flight of the aircraft which has the upgraded FMS systemon board. Like the preexisting flight management system, the upgradedflight management system of the present invention may employ a redundantsystem connected to the legacy AFMC so that, for example, the pilot andfirst officer each have a duplicate set of controls. In such aninstance, the upgraded system of the present invention would include asecond IRU, a second CADC, a second DME receiver, a second DFGC, asecond data concentrator unit, and a second global positioning receiverwhile still utilizing the common legacy AFMC. Thus, as will be explainedin greater detail below with reference to the drawings, the upgradedflight management system of the present invention provides a viable andcost effective solution to upgrade a preexisting flight managementsystem while increasing functionality and overcoming shortcomings of thepreexisting system, such as, for example, increasing FMS navigationdatabase storage capacity, providing RNP VNAV and RNAV capabilityutilizing a GPS based navigation solution, and providing required timeof arrival or RTA capability.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate further description and understanding of the presentinvention, the following drawings are provided in which:

FIG. 1 is a representative block diagram illustrating a typicalconventional prior art preexisting legacy flight management system, suchas the legacy MD-80/90 Nav System available on a conventional MD-80/90commercial aircraft;

FIG. 2 is a representative block diagram illustrating the upgradedpreexisting flight management system, according to the present inventionin which the system of FIG. 1 has been upgraded in accordance with thepresent invention;

FIG. 3A is a representative diagrammatic illustration of an MD-80/90aircraft with the upgraded preexisting flight management system of FIG.2 on board;

FIG. 3B is a representative system flow chart of the software employedto carry out the related functions of the Navigator portion of the MCDUin the upgraded system of FIG. 2;

FIG. 4 is a representative flow chart illustrating a typical preferredmethod in accordance with the present invention for upgrading apreexisting flight management system, such as the flight managementsystem of FIG. 1, to achieve the presently preferred embodimentillustrated in FIG. 2.

FIG. 5 is a diagrammatic illustration comparing an exemplary standardflight plan generated by the upgraded flight management system of FIG. 2to an alternate loaded flight plan;

FIG. 6 is a diagrammatic illustration of an exemplary AFMCinitialization page accessible through the MCDU in the upgraded flightmanagement system of the present invention as illustrated in FIG. 2;

FIGS. 7A and 7B are diagrammatic illustrations of an exemplary AFMCposition initialization and position reference page, respectively,accessible through the MCDU in the upgraded flight management system ofthe present invention as illustrated in FIG. 2;

FIG. 8 is a diagrammatic illustration of an exemplary AFMC performanceinitialization page accessible through the MCDU in the upgraded flightmanagement system of the present invention as illustrated in FIG. 2;

FIG. 9 is a diagrammatic illustration of an exemplary AFMC takeoffreference page accessible through the MCDU in the upgraded flightmanagement system of the present invention as illustrated in FIG. 2;

FIG. 10 is a diagrammatic illustration of an exemplary AFMC approachreference page accessible through the MCDU in the upgraded flightmanagement system of the present invention as illustrated in FIG. 2;

FIG. 11 is a diagrammatic illustration of an exemplary legacy AFMC LEGSpage transferred to the AFMC using the MCDU interface in accordance withthe upgraded flight management system of the present invention asillustrated in FIG. 2;

FIG. 12 is a diagrammatic illustration of an exemplary AFMC climb pageaccessible through the MCDU in accordance with the upgraded flightmanagement system of the present invention as illustrated in FIG. 2;

FIG. 13 is a diagrammatic illustration of an exemplary AFMC engine outclimb page accessible from the climb page of FIG. 12 in accordance withthe present invention in the upgraded flight management system of FIG.2;

FIG. 14 is a diagrammatic illustration of an exemplary AFMC economycruise page accessible from the MCDU in accordance with the upgradedflight management system of the present invention as illustrated in FIG.2;

FIG. 15 is a diagrammatic illustration of an exemplary AFMC engine outcruise page accessible from the cruise page of FIG. 14 in accordancewith the present invention in the upgraded flight management system ofFIG. 2;

FIG. 16 is a diagrammatic illustration of an exemplary AFMC economydescent page accessible from the MCDU in accordance with the upgradedflight management system of the present invention as illustrated in FIG.2; and

FIG. 17 is a diagrammatic illustration of an exemplary AFMC descentforecast page accessible from the descent page of FIG. 16 in accordancewith the present invention in the upgraded flight management system ofFIG. 2.

For simplicity and clarity of illustration, the drawing figuresillustrate the general manner of construction, and descriptions anddetails of well-known features and techniques may be omitted to avoidunnecessarily obscuring the invention. Additionally, elements in thedrawing figures are not necessarily drawn to scale. For example, thedimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help improve understanding of embodimentsof the present invention. The same reference numerals in differentfigures denote the same elements.

The terms “first,” “second,” “third,” “fourth,” and the like in thedescription and in the claims, if any, are used for distinguishingbetween similar elements and not necessarily for describing a particularsequential or chronological order. It is to be understood that the termsso used are interchangeable under appropriate circumstances such thatthe embodiments described herein are, for example, capable of operationin sequences other than those illustrated or otherwise described herein.Furthermore, the terms “include,” and “have,” and any variationsthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, system, article, device, or apparatus that comprises alist of elements is not necessarily limited to those elements, but mayinclude other elements not expressly listed or inherent to such process,method, system, article, device, or apparatus.

The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,”“under,” and the like in the description and in the claims, if any, areused for descriptive purposes and not necessarily for describingpermanent relative positions. It is to be understood that the terms soused are interchangeable under appropriate circumstances such that theembodiments of the invention described herein are, for example, capableof operation in other orientations than those illustrated or otherwisedescribed herein.

The terms “connect,” “connected,” “connects,” “connecting,” “couple,”“coupled,” “couples,” “coupling,” and the like should be broadlyunderstood and refer to linking two or more elements or signals,electrically, mechanically and/or otherwise. Two or more electricalelements may be electrically connected/coupled but not be mechanicallyor otherwise connected/coupled; two or more mechanical elements may bemechanically connected/coupled, but not be electrically or otherwiseconnected/coupled; two or more electrical elements may be mechanicallyconnected/coupled, but not be electrically or otherwiseconnected/coupled. Connecting/coupling may be for any length of time,e.g., permanent or semi-permanent or only for an instant.

“Electrical connecting,” “electrical coupling,” and the like should bebroadly understood and include connecting/coupling involving anyelectrical signal, whether a power signal, a data signal, and/or othertypes or combinations of electrical signals. “Mechanical connecting,”“mechanical coupling,” and the like should be broadly understood andinclude mechanical connecting/coupling of all types.

The absence of the word “removably,” “removable,” and the like near theword “connected” and/or “coupled,” and the like does not mean that theconnecting and/or coupling, etc. in question is or is not removable.

The term “primary” in the description and in the claims, if any, is usedfor descriptive purposes and not necessarily for describing relativeimportance. For example, the term “primary” can be used to distinguishbetween a first component and an equivalent redundant component;however, the term “primary” is not necessarily intended to imply anydistinction in importance between the so-called primary component andthe redundant component. Unless expressly stated otherwise, anyredundant component(s) should be treated as being able to operateinterchangeably with any primary component(s) of the system, in tandemwith any primary component(s), and/or in reserve for any primarycomponent(s) (e.g., in the event of a component/system failure).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, and initially to FIG. 1, it isbelieved that a brief explanation of FIG. 1, which illustrates a typicalprior art legacy MD-80/90 Nav system 100 of the type normally found onboard conventional MD-80/90 aircraft, would be helpful in understandingthe subsequent explanation of the upgrading of such a legacy system 100in accordance with the present invention. For purposes of illustration,a presently preferred embodiment of such an upgraded flight managementsystem 200 is illustrated in FIG. 2, with like reference numerals beingutilized in FIG. 2 for the preexisting or legacy components of thepreexisting flight management system of FIG. 1 which remain after theupgrading of the system of FIG. 1 has taken place in accordance with thepresent invention. As illustrated in FIG. 1, the prior art orpreexisting flight management system 100 which is to be upgraded inaccordance with the present invention will be described, by way ofexample, with reference to a conventional legacy MD-80/90 Nav system ofthe type normally provided on board preexisting MD-80/90 aircraftprovided by the Boeing Company and previously through McDonnell DouglasCorporation now a part of the Boeing Company.

As shown in FIG. 1, the conventional prior art preexisting flightmanagement system or FMS 100 provided on board a typical MD-80/90aircraft, normally includes redundant systems for the pilot and firstofficer. The redundant FMS system 100 which preexisting MD-80/90aircraft are normally equipped with includes two conventional inertialreference units or IRU 110, 120; two conventional VHF NAV receivers 116,118; two conventional DME receivers 112, 122; a conventional markerbeacon receiver 119; two conventional multipurpose control display unitsor MCDU 130, 132; a common conventional advance flight managementcomputer or AFMC 105; two conventional central air data computers orCADC 111, 121; and two conventional flight guidance computers or DFGC113, 123. In addition, as also illustrated in FIG. 1, the preexistingconventional FMS system 100 also normally includes conventional symbolgenerators 134, 136; a conventional system clock 138 for providing GMTto the AFMC 105; two conventional VHF omnidirectional radios or VOR 140,142; two convential DME tuning converters 144, 146; and a pair ofconventional flight displays 148, 150 for conventionally displayingflight information to the pilot and first officer comprising the flightcrew. As further illustrated in FIG. 1, the IRUs 110, 120 are connectedto the AFMC 105, and to the symbol generators 134, 136, respectively,through an ARINC 429 data bus; the CADCs 111, 121 are connected to theAFMC 105, and to the symbol generators 134, 136, respectively, throughan ARINC 575 data bus; and the DMEs 112, 122, the VORs 140, 142, and theDFGCs 113, 123, are connected to the AFMC 105 through an ARINC 429 databus as well. In the conventional prior art legacy MD-80/90 navigationsolution illustrated by the FMS system 100 of FIG. 1, the common AFMC105 is utilized to calculate Lateral Guidance, Vertical Guidance, andPerformance Calculations for the aircraft. In so doing, the AFMC 105relies on dual INU input for position data and conventionally generatesa blended position solution by applying corrections based on DMEdistance from known references.

As will be explained in greater detail below, with reference to FIG. 2and the other figures, the upgraded FMS system 200 of the presentinvention is believed to provide a viable and cost effective solutionfor upgrading preexisting flight management systems, such as thepreexisting flight management system or FMS 100 illustrated in FIG. 1,preferably increasing functionality and overcoming existing systemshortcomings, given today's requirements, found to be present in priorart flight management systems, such as the prior art FMS system 100illustrated in FIG. 1. For example, as will be explained below, it isexpected that the upgraded FMS system 200 of the present invention, willincrease the FMS Navigation database storage capacity, provide RNP VNAVand RNAV capability utilizing a GPS based navigation solution, and/orprovide Required Time of Arrival or RTA capability, all of which assistin increasing the functionality of and overcoming system shortcomings ofthe prior art preexisting FMS system 100 being upgraded in accordancewith the present invention.

Referring now to FIG. 2, FIG. 2 illustrates an upgraded preexistingflight management system (FMS) 200 in accordance with the presentinvention, with any preexisting components of the preexisting FMS system100 which is being upgraded which remain in the upgraded FMS system 200having the same reference numerals as utilized in FIG. 1. The upgradedpreexisting FMS system 200 being described with reference to FIG. 2 ismerely exemplary of such upgraded systems in accordance with the presentinvention and the invention is not intended to be limited to theembodiments presented herein.

As shown and preferred in FIG. 2, the upgraded FMS system 200 preferablyretains the legacy AFMC 105 previously present in the preexisting flightmanagement system 100 as well as the legacy IRUs 110, 120, CADCs 111,121, VHF NAV Receivers 116, 118, DME Receivers 112, 122, and DFGCs 113,123. The legacy AFMC 105 is preferably retained in the upgraded FMSsystem 200 in order to exploit its previously proven performancecapabilities. The preexisting MCDUs 130, 132 are preferably replacedwith new MCDUs 225, 255 which preferably contain navigation computers280, 282 which manage the flight plan and generate lateral and verticalguidance, auto throttle controls, and configure and synchronize thelegacy AFMC 105 to allow it to continue to calculate the aircraftperformance parameters throughout the flight. Preferably the AFMCperformance based pages which appear on the MCDU 225, 255 are accessiblethrough the MCDUs 225, 255 via ARINC 739 protocol, with such performancebased pages being illustrated, by way of example, in FIGS. 6-17.

Preferably, the AFMC 105 performance data in the upgraded FMS system 200of FIG. 2 is utilized to provide estimated time of arrival for each legof the flight and to the final destination; predicted leg speed andaltitude leg cruise winds; progress such as distance to go, ETA and fuelremaining; current speed mode such as parameters associated withLRC/ECON, selected airspeed or mach, limited speed such as VMO, MMO,Flap, Alpha; speed override, and engine out mode; top of descent; top ofclimb; step climbs; and fuel quantity and fuel used. The desired flightplan route is preferably entered into and calculated by the NAV computer280, 282, which is preferably RNP capable. In the presently preferredsystem 200 of the present invention, the flight planning pages areformatted to replicate the existing AFMC 105 pages. Preferably, a subsetof the flight plan is automatically transferred to the legacy AFMC 105from the NAV computers 280, 282 located in the MCDUs 225, 255,respectively, via a conventional ARINC 739 interface therebetween.Preferably, in the upgraded FMS system 200 of the present invention,this subset of the flight plan consists of the origin, destination andinterim waypoints. Waypoints on the SIDS and STAR are preferablytransferred to the legacy AFMC 105 via lat long data since the AFMC 105database in accordance with the present invention will not include allrequired terminal procedures thereby allowing it to hold a smallerdatabase, thereby assisting the upgraded FMS system 200 in overcomingmemory limitation issues present in the preexisting FMS system 100.

Preferably, in the upgraded FMS system 200 of the present invention, thelegacy AFMC 105 now preferably calculates the top of descent and top ofclimb waypoints based on best performance for the aircraft and transmitsthese waypoints on an ARINC 702 data bus to respective data concentratorunits 201, 251. The DCUs 201, 251 are respectively connected to the NAVcomputers 280, 282, and preferably relay this information to the NAVcomputers 280, 282 which, preferably, in turn, include them in theflight profile for the aircraft.

The AFMC 105 preferably provides an interface page which allows forwaypoint insertion referenced by Latitude and Longitude. Depending onthe legacy AFMC 105 employed, this interface may be limited by format,such as to 1/10^(th) of a minute or one decimal place accuracy for bothLatitude and Longitude values. In such an instance, the resolution ofthe equivalent AFMC waypoint would be limited, such as to approximately608 feet; however, it is believed that such an inaccuracy would not besignificant to the Performance solution calculated by the AFMC 105, andwould not be relevant to the Lateral and Vertical guidance provided bythe NAV computers 280, 282.

Referring now to the inertial reference units or IRUs 110, 120 employedin the upgraded FMS system 200 of the present invention, these IRUs 110,120 are the primary source of position data, i.e. latitude andlongitude, utilized by the legacy AFMC 105 to generate the navigationsolution for the upgraded FMS system 200. It is a known fact thatnormally the IRU position is most accurate immediately afterinitialization or alignment and normally degrades throughout the flightuntil such time as the IRU is realigned. In the presently preferredupgraded FMS system 200 of the present invention, the NAV computers 280,282 preferably rely on the position data from the IRUs 110, 120,respectively, augmented with conventional dual Beta 3 GPS receivers 202,252, respectively, for primary navigation. Preferably, a Kalman filteralgorithm is utilized to blend the GPS data with the IRU position data,with this blended GPS/IRU data preferably being transmitted to the AFMC105 in place of the normal IRU generated data. In accordance with thepresent invention, in instances where the GPS data may not be availablefor any extended amount of time, data from the DME Receivers 112, 122 ispreferably used to augment the IRU position information. In addition,preferably the NAV computers 280, 282 may include an MCDU page whichcould allow the IRUs 110, 120 to be aligned while the aircraft is at thegate. Furthermore, preferably the IRU 110, 120 position can bere-initialized using GPS position and time data if desired.

In the presently preferred upgraded FMS system 200 of the presentinvention, the NAV computers 280, 282 preferably interface directly withthe digital flight guidance computers or DFGC 113, 123, respectively, inorder to maintain control authority of the provided autopilot and theauto-throttle functions at all times.

Furthermore, the presently preferred navigation solution provided by theupgraded FMS system 200, in addition to the aforementioned class Beta-3GPS receivers 202, 252, utilizes two conventional TSO-C190 antennas,with the GPS receivers 202, 252, by way of example, being TSO-C145cclass Beta-3 GPS receivers. The resultant GPS signal is preferably fedto the respective DCUs 201, 251 to be used for augmentation of positioninformation from the IRUs 110, 120, respectively.

The presently preferred navigation solution in the upgraded FMS system200 is preferably built around the two NAV computers 280, 282, which, byway of example, are DO-229D, DO-238A and DO-236B compliant and RNPcapable. These NAV computers 280, 282, by way of example, areTSO-C146c-Gamma 3 compliant with additional RNAV and VNAV RNPcapabilities and are preferably respectively housed within the MCDU 225,255 enclosure for reducing space and power requirements although, ifdesired, they need not be housed there. By way of example, in theillustrated FMS system 200 of the present invention, described withrespect to the MD-80/90 FMS system, each of the NAV computers 280, 282is preferably RNP 0.3 capable without the database limitations of thepreexisting AFMC 105. Preferably, the FMS menu structure in the upgradedFMS system 200 replicates that of the preexisting AFMC 105 but providesadditional features designed to emulate the conventional styled menus.

Each of the MCDUs 225, 255 preferably contains microprocessors makingthem capable of performing control logic, something which is unavailablein the legacy equipment being upgraded. Each MCDU 225, 255 preferablysupports peripheral equipment, such as ACARS, through conventional ARINC739A compliant interfaces, with the respective MCDUs 225, 255 alsopreferably acting as the interface to the AFMC 105 via an ARINC 739Ainterface as well.

The NAV computers 280, 282 in the present invention are preferably ableto calculate Required Time of Arrival or RTA for any flight planwaypoint as well as required leg airspeed to meet RTA constraints. Thepresently preferred NAV computers 280, 282 preferably provide RTAcapabilities to any specific waypoint through the LEGS menu page. Inthis regard, when an RTA is established at one of the flight planwaypoints, the respective NAV computer 280, 282 commands the leg speedsfor the legs leading up to that waypoint to achieve the required time ofarrival. Preferably a boundary checking of the commanded airspeed isperformed to assure that the aircraft is being operated within a safeairspeed envelope and a warning is preferably provided to the pilot ifthe RTA is not obtainable due to safe airspeed restrictions.

The AFMC 105 preferably continuously calculates the estimated time ofarrival or ETA for each of the legs in the flight plan based on thecurrent aircraft performance and the NAV computer 280, 282 uses this ETAto determine the speed needed to reach the designated waypoint at theRTA. Preferably, as the flight progresses, the NAV computers 280, 282monitor the calculated ETAs and modify the leg speeds accordingly. Eachflight plan leg is preferably analyzed to determine the appropriatespeed constraints which need to be followed, with the AFMC 105 leg speedbased on best performance preferably being used by the NAV computer 280,282 in cases where an RTA has not been specified.

Preferably, flight path discontinuities are resolved by the NAVcomputers 280, 282 and transmitted to the AFMC 105 as flight planmodifications. Although the AFMC 105 normally assumes direct point topoint legs when its flight plan is created by connectingLatitude/Longitude coordinates, any slight deviation, such as due toflight path discontinuities, preferably does not create a significanterror in the AFMC 105 computed performance data. Transferring the flightplan using Latitude/Longitude coordinates excludes all curved RF typelegs which can result in a deviation from the defined path. However,this deviation can be minimized in accordance with the present inventionby inserting additional waypoints to approximate the curved path and,hence, minimize any significant impact on the performance calculationsof the AFMC 105. This is illustrated in FIG. 5 which illustrates thetransfer of curved legs to the AFMC 105. It should be noted that whilespeed constraints may be manually entered per leg to satisfy RTArequirements or determined from the AFMC 105, constraints associatedwith published procedures and aircraft limitations would preferably beused to provide a not to exceed envelope for airspeed. Preferably theRTA can be primarily achieved by adjusting the speeds prior to top ofdescent.

As discussed above various performance calculations are preferablyobtained from the AFMC 105 and used by the navigation computers 280,282. For example, the ETA for each leg and to the final destination, ispreferably made available to the navigation computers 280, 282 byquerying the AFMC 105 via the A739 progress page. The information ispreferably received via textual data and is translated by the navigationcomputers 280, 282 to numeric format. The navigation computers 280, 282then preferably use this data to cross check the RTA performance.

Another performance calculation is preferably the predicted leg speedand altitude leg cruise winds. Generally, this information is notrequired by the navigation computers 280, 282 and is only displayed forpilot information and modification as part of the conventional A739interface. Similarly, distance to go, ETA, and fuel remaining are alsonot generally required by the navigation computers 280, 282 and are onlydisplayed for pilot information. This is also preferably true forcurrent speed modes and fuel quantity and fuel used as well, which arenot required by the navigation computers 280, 282 and only displayed forpilot information and modification as part of the conventional A739interface.

Still another performance calculation is top of descent which ispreferably calculated based on the pilot entry of end of descent. Thisinformation is preferably transmitted from the AFMC 105 to the DCUs 201,251 via ARINC 702 protocol and inserted to the flight profile by thenavigation computers 280, 282 after boundary check are performed on thedata. Preferably, at the top of descent, the navigation computers 280,282 command idle thrust and pitch down to track the target airspeedobtained from the AFMC/DFGCs 105, 113, 123 transmit bus. The commandairspeed is preferably boundary checked by the navigation computers 280,282 prior to transmission to the respective DFGCs 113, 123. Preferably,any modifications to the target EPR and/or target airspeed is monitoredand passed along to the respective DFGCs 113, 123 after boundarychecking is performed by the navigation computers 280, 282.

Yet another performance calculation which is preferably performed is topof climb which is preferably calculated based on the climb limit thrustto each altitude constraint. The top of climb is preferably transmittedfrom the AFMC 105 to the DCUs 201, 251 via ARINC 702 protocol andinserted to the flight profile by the respective navigation computers280, 282. Preferably, during the climb, the AFMC 105 calculates requiredthrust and pitch. The navigation computers 280, 282 command climb limitthrust and pitch to track the profile obtained from the AFMC/DFGCs 105,113, 123 transmit bus. The commands are preferably boundary checked bythe navigation computers 280, 282 prior to transmission to therespective DFGCs 113, 123. Preferably, any modifications to theauto-throttle commands and/or pitch is monitored and passed along to therespective DFGCs 113, 123 after boundary checking is performed by thenavigation computers 280, 282.

Still another performance calculation preferably being performed are thestep climb points which are preferably calculated by the AFMC 105 basedon optimum altitude and selected economy modes. Preferably, during theclimb of the aircraft, the AFMC 105 calculates required thrust andpitch. The navigation computers 280, 282 preferably command climb limitthrust and pitch to track the profile obtained from the AFMC/DFGCs 105,113, 123 transmit bus. The commands are preferably boundary checked bythe navigation computers 280, 282 prior to transmission to therespective DFGCs 113, 123. As with the top of climb, for step climbs aswell, any modifications to the auto-throttle commands and/or pitch ispreferably monitored and passed along to the DFGCs 113, 123 afterboundary checking is performed by the respective navigation computers280, 282.

As was previously discussed, the navigation computers 280, 282preferably govern the auto-throttle, pitch and roll commands to therespective DFGC 113, 123 during all phases of flight of the aircraft.During the approach phase for the aircraft, less priority is preferablygiven to the performance related pitch and auto-throttle commandsprovided by the AFMC 105. The control command are preferably computedand enforced by the navigation computers 280, 282 to maintain thevertical, horizontal and optimum airspeeds for the required approachpath for the aircraft through final approach. Preferably, guidanceduring missed approach for the aircraft is also computed and maintainedby the navigation computers 280, 282 in order to meet RNP requirements.

With respect to the menu interface being preferably provided, the MCDU225, 255 preferably utilizes the existing AFMC 105 menu structure viathe ARINC 739 protocol for all performance pages. The navigationcomputers 280, 282 preferably replicate the menu structure of theexisting AFMC 105 for flight planning in order to help minimize pilottraining on the upgraded system 200 so as to, preferably, help make theoperations of the upgraded FMS system 200 of the present invention asseamless a transition as possible from the prior preexing flightmanagement system 100 which the flight crew had been familiar with onthe aircraft in which the FMS system has been upgraded. In this regard,preferably the navigation computers 280, 282 maintain absoluteunderstanding of the AFMC 105 menu structure at all times and react topilot entries in the same manner as in the preexisting legacy AFMC 105.For example, the navigation computers 280, 282 transfer the flight planinformation to the AFMC 105 via ARINC 739 protocol in the same way thatthe AFMC 105 expects it from the MCDU 225, 255. Furthermore, thecommunications with the AFMC 105 is preferably based on automated use ofthe MCDU 225, 255 page interfaces, with the FMS system 200 of thepresent invention preferably allowing direct access to the AFMC 105performance pages and automating communications for the variousparameters located on other AFMC 105 performance pages, as will bediscussed in greater detail with respect to FIGS. 6-17.

As shown and presently preferred in FIG. 2, the displays 148 and 150 ofFIG. 1 may be comprised of conventional integrated flat panel displays235, 265, respectively, having associated conventional display controlpanels 230, 260, respectively, with the respective display controlpanels 230, 260 being connected between the associated flat paneldisplay 235, 265 and the corresponding MCDU 225, 255, as well as beingconnected to the respective DCU 201, 251, as shown in FIG. 2.

As diagrammatically illustrated in FIG. 3A, the presently preferredflight management system 200 is located on board the aircraft 300 forenabling control of the aircraft 300 by the flight crew. As waspreviously mentioned, the legacy AFMC 105 contained in the upgraded FMSsystem 200 on board the aircraft 300 is preferably still able to exploitits aircraft performance capabilities throughout the flight of theaircraft 300. In this regard, as will be explained below with referenceto FIGS. 6-17, since, preferably, the legacy AFMC 105 is what isutilized for performance calculations in the upgraded FMS system 200 ofthe present invention, the menu pages relating to performance arepreferably directly accessible through the MCDU 225, 255. In thisregard, these initialization pages include such pages as PERFORMANCEINIT, TAKEOFF REF, and APPROACH REF.

Before describing the performance pages in greater detail, suffice it tosay that, FIG. 3B, by way of example, illustrates a typicalrepresentative system flow chart for the software employed to enable therelated functions described above of the navigation computers 280, 282located in the respective MCDUs 225, 255 to be carried out. For example,the navigator computers 280, 282 may be conventionally programmed in Cto carry out the functions illustrated in the system flow chart of FIG.3B. Suffice it say that in accordance with the system flow chart of FIG.3B, the MCDU/NAV units act as the primary interface to the pilot forflight planning purposes. The MCDU/NAV internal navigation database isutilized to retrieve information regarding the various navigation pointsand aid in computation of the planned flight path. The planned flightpath is then transferred to the legacy AFMC 105 to allow it toconventionally compute performance parameters for optimum fuel burn andtime en-route. The legacy AFMC 105 thrust and airspeed targets are thenconventionally analyzed by the navigation computers 280,282 and a finalset of lateral, vertical, thrust and airspeed targets are then providedto the DFGCs 113,123. The system flow chart is self-explanatory and neednot be described in further greater detail in order to understand thepresently preferred operation of the navigation computers 280, 282 inthe upgraded FMS system 200 of the present invention.

Referring now to FIG. 6, at least one menu page can comprise an AFMCInitiation Page for providing performance calculations to legacy AFMC105 (FIG. 2). Preferably, the AFMC Initiation Page can permit access toat least one of the Performance Initiation Page, the Takeoff ReferencePage, or the Approach Reference Page, as described below.

Referring now to FIGS. 7A and 7B, at least one menu page can comprise aPosition Initialization Page (FIG. 7A) and another menu page cancomprise a Position Reference Page (FIG>7B). The Position InitializationPage (FIG. 7A) can allow for initialization and/or verification of IRU110, 120 (FIG. 2) and/or selections for legacy AFMC 105 (FIG. 2),whereas the Position Reference Page (FIG. 7B) allows for verification ofposition.

Referring now to FIG. 8, at least one menu page can comprise aPerformance Initiation Page. The Performance Initiation Page can allowfor entry of fuel, weight, and/or performance configurations to beprovided to legacy AFMC 105 (FIG. 2).

Referring now to FIG. 9, at least one menu page can comprise a TakeoffReference Page. The Takeoff Reference Page can allow for entry oftakeoff performance and reference speed configurations to be provided tolegacy AFMC 105 (FIG. 2).

Referring now to FIG. 10, at least one menu page can comprise anApproach Reference Page. The Approach Reference Page can allow for entryof approach performance and reference speed configurations to beprovided to legacy AFMC 105 (FIG. 2).

Referring now to FIG. 11, at least one menu page can comprise a legacyAFMC LEGS Page, labeled in the illustrative example as “ACT RTE 1 LEGS”.This menu page illustrates the actual route 1 LEGS Page transferred tothe legacy AFMC 105 (FIG. 2) using the MCDU interface in accordance withthe present invention.

Referring now to FIG. 12, at least one menu page can comprise the AFMCCLIMBS Page, as referenced above, labeled “ACT 250KT CLB” in the exampleshown. This Page can display such parameters as cruise altitude and/orspeed details for each leg of a flight of aircraft 300 (FIG. 3).

In various embodiments, at least one menu page can comprise a Route MenuPage (not shown). In such an instance, the Route Menu Page can providean interface by which to enter flight plans to be provided to VHF NAVreceiver 116 (FIG. 2) and/or legacy AFMC 105 (FIG. 2). In furtherembodiments, at least one menu page can comprise a Holding Menu Page(not shown) to define holding patterns at a selected waypoint of theflight plans.

In other embodiments, at least one menu page can comprise a Departureand/or Arrival Page (not shown) to select departure and/or arrivalprocedures to be provided to VHF NAV receiver 116 (FIG. 2). Thedeparture and/or arrival procedures can be stored within a navigationdatabase of VHF NAV receiver 116 (FIG. 2) and transferred to legacy AFMC105.

In various embodiments, at least one menu page can comprise one or moreProgress Pages (not shown), each displaying at least one of an altitude,a distance remaining, an ETA, or a fuel burn for each of the legs in aflight plan of aircraft 300 (FIG. 3A). In such an instance, any of thisdata can automatically be retrieved from legacy AFMC 105 (FIG. 2).Furthermore, at least one menu page can comprise a Fix Page (not shown)for querying the navigation database of VHF NAV receiver 116 for fixinformation. In addition, at least one menu page can comprise a ClimbPage for selecting climb performance modes and/or for specifying climbconstraints (e.g., cruising altitude, climb mode, speed constraints,etc.) for aircraft 300 (FIG. 3A).

Referring now to FIG. 13, in some embodiments, the menu page cancomprise an Engine Out Climb Page. In such an instance, the Engine OutClimb Page can provide an interface by which to recalculate climbperformance based on single engine performance data. In variousembodiments, the Engine Out Climb Page can be accessed through the ClimbPage, as described above.

Referring now to FIG. 14, in some embodiments, the menu page cancomprise a Cruise Page selecting cruise performance modes and/or forspecifying cruise constraints (e.g., cruising altitude, drift downaltitude, cruise airspeed, minimum safe operating speed, etc.) foraircraft 300 (FIG. 3A), such as the economy values illustrated in FIG.14. Referring now to FIG. 15, the menu page can comprise an Engine OutCruise Page to provide an interface by which to recalculate cruiseperformance based on single engine performance data. In manyembodiments, the Engine Out Cruise Page and a Cruise Drift Down Page(not shown) can be accessible from the Cruise Page.

Referring now to FIG. 16, the menu page can comprise a Descent Page forproviding an interface to define the descent phase of flight, such asthe economy values illustrated in FIG. 16. In such an instance, thelegacy AFMC 105 (FIG. 2) can be configured to entries provided via theDescent Page to determine and commence descending at the top of decentpoint.

Referring now to FIG. 17, the menu page can comprise a Descent ForecastPage for providing an interface to define additional descent parameters(e.g., forecast winds, anti-icing, etc.).

Returning back now to FIG. 4, FIG. 4 illustrates an exemplary flow chartof a method 400 of upgrading a preexisting FMS, such as FMS system 100previously described, having a legacy AFMC 105 in order to provideincreased functionality over the preexisting FMS 100 for enabling theupgraded preexisting FMS 200 to be capable of having at least increasednavigation database storage capacity; and/or RNP, VNAV and RNAVcapability utilizing a GPS based navigation solution and/or RTAcapability while still enabling the legacy AFMC to exploit its aircraftperformance capabilities throughout the flight of an aircraft 300 havingthe upgraded preexisting FMS 200 on board. The method 400 illustrated inFIG. 4 is merely intended to be exemplary and is not limited to theembodiments of the FMS system 200 presented herein. Method 400 can beemployed in many different embodiments or examples not specificallydepicted or described herein. In some embodiments, the activities, theprocedures, and/or the processes of method 400 can be performed in theorder presented. In other embodiments, the activities, the processes,and/or the procedures of method 400 can be performed in any othersuitable order. In still other embodiments, one or more of theactivities, the processes, and/or the procedures in method 400 can becombined or skipped. Thus, FIG. 4 is just an illustration of the varioussteps that may be preferably performed to achieve the presentlypreferred upgraded FMS system 200 of the present invention from thepreexisting FMS system 100 originally provided on board the aircraft300, keeping in mind that the steps need not be performed in anyspecific order as long as they ultimately result in the upgraded FMSsystem 200 of FIG. 2.

Of course any modifications may be made to the upgraded system 200 andmethod described herein as long as such modifications do not depart fromthe spirit and scope of the present invention as set forth herein in thespecification and in the claims below.

1. In an upgraded preexisting FMS having increased functionality over apreexisting FMS, the preexisting FMS having a legacy AFMC havingaircraft performance capabilities exploitable throughout a flight of anaircraft having the preexisting FMS on board the aircraft; an IRU, aCADC, a DME receiver, and a DFGC, the IRU, CADC, DME receiver and DFGCbeing in communication with the legacy AFMC; the improvement comprisinga data concentrator unit, the CADC, IRU and DME receiver being connectedto the data concentrator unit for providing input information thereto,the data concentrator unit and the legacy AFMC being operativelyconnected to each other for exchanging input and output informationtherebetween, the DFGC being connected to the data concentrator unit forreceiving output information therefrom; and a global positioning systemreceiver operatively connected to the data concentrator unit forproviding input information thereto; whereby the upgraded preexistingFMS is capable of at least increased navigation database storagecapacity; and/or RNP, VNAV and RNAV capability utilizing a GPS basednavigation solution and/or RTA capability, while still enabling thelegacy AFMC to exploit its aircraft performance capabilities throughoutthe flight of an aircraft having the upgraded preexisting FMS on board.2. An upgraded preexisting FMS in accordance with claim 1 furthercomprising an MCDU operatively connected to the data concentrator unitand the legacy AFMC for exchanging information therebetween.
 3. Anupgraded preexisting FMS in accordance with claim 2 further comprising adisplay control panel operatively connected to the data concentratorunit for exchanging information therebetween.
 4. An upgraded preexistingFMS in accordance with claim 3 further comprising an integrated flatpanel display operatively connected to the data concentrator unit forexchanging information therebetween.
 5. An upgraded preexisting FMS inaccordance with claim 1 further comprising a display control paneloperatively connected to the data concentrator unit for exchanginginformation therebetween.
 6. An upgraded preexisting FMS in accordancewith claim 5 further comprising an integrated flat panel displayoperatively connected to the data concentrator unit for exchanginginformation therebetween.
 7. An upgraded preexisting FMS in accordancewith claim 1 further comprising an integrated flat panel displayoperatively connected to the data concentrator unit for exchanginginformation therebetween.
 8. An upgraded preexisting FMS in accordancewith claim 1 further comprising a redundant system operatively connectedto the legacy AFMC, the redundant system comprising a second IRU, asecond CADC, a second DME receiver, a second DFGC, a second dataconcentrator unit, and a second global positioning system receiver. 9.An upgraded preexisting FMS in accordance with claim 8 wherein thesecond CADC, IRU and DME receiver are connected to the second dataconcentrator unit for providing redundant input information thereto, thesecond CADC being further connected to the legacy AFMC for providingredundant input information thereto, the second data concentrator unitand the legacy AFMC being operatively connected to each other forexchanging redundant input and output information therebetween, thesecond DFGC being connected to the second data concentrator unit forreceiving output information therefrom, the second global positioningsystem receiver being operatively connected to the second dataconcentrator unit input; whereby the redundant system shares the legacyAFMC in the upgraded FMS.
 10. An upgraded preexisting FMS in accordancewith claim 9 further comprising a second MCDU operatively connected tothe second data concentrator unit and the legacy AFMC for exchanginginformation therebetween.
 11. An upgraded preexisting FMS in accordancewith claim 10 further comprising a second display control paneloperatively connected to the second data concentrator unit forexchanging information therebetween.
 12. An upgraded preexisting FMS inaccordance with claim 11 further comprising a second integrated flatpanel display operatively connected to the data concentrator unit forexchanging information therebetween.
 13. An upgraded preexisting FMS inaccordance with claim 1 further comprising a VHF NAV receiver forproviding NAV information to the upgraded preexisting FMS.
 14. A methodof upgrading a preexisting FMS having a legacy AFMC in order to provideincreased functionality over the preexisting FMS for enabling theupgraded preexisting FMS to be capable of having at least increasednavigation database storage capacity; and/or RNP, VNAV and RNAVcapability utilizing a GPS based navigation solution and/or RTAcapability while still enabling the legacy AFMC to exploit its aircraftperformance capabilities throughout the flight of an aircraft having theupgraded preexisting FMS on board, the preexisting FMS having at least alegacy AFMC, an IRU, a CADC, a DME receiver, a DFGC, and a legacy EFIS,the IRU, CADC, DME receiver and DFGC being in communication with thelegacy AFMC; the method comprising the steps of replacing the legacyEFIS system with a data concentrator unit; connecting the CADC, IRU andDME receiver to the data concentrator unit for providing inputinformation thereto; connecting the data concentrator unit and thelegacy AFMC together for exchanging input and output informationtherebetween; connecting the DFGC to the data concentrator unit outputfor receiving output information therefrom; and adding a globalpositioning system receiver to the preexisting FMS and operativelyconnecting it to the data concentrator unit input.
 15. A method ofupgrading a preexisting FMS in accordance with claim 14 furthercomprising the step of operatively connecting an MCDU to the dataconcentrator unit and the legacy AFMC for exchanging informationtherebetween.
 16. A method of upgrading a preexisting FMS in accordancewith claim 15 further comprising the step of connecting the dataconcentrator unit to a display control panel for exchanging informationtherebetween.
 17. A method of upgrading a preexisting FMS in accordancewith claim 16 further comprising the step of operatively connecting thedata concentrator unit to an integrated flat panel display forexchanging information therebetween.
 18. A method of upgrading apreexisting FMS in accordance with claim 14 further comprising the stepof providing a VHF NAV receiver for providing NAV information to the FMSsystem.